The present invention relates to asphaltic compositions, which have been chemically modified by reacting the asphalt with a monomer.
It is known that the properties of asphalt cement can be improved by adding modifiers such as polymers, fibers, carbon, sulfur, etc. to the asphalt composition. These modifications have resulted in improved physical properties of asphalt and the development of specific asphalt products for special applications. A variety of approaches have been used in modifying the asphalt cement with polymers. These approaches encompass dispersing or dissolving the polymers in the asphalt cement and grafting the polymer to the bitumen in the asphalt by reacting the polymer and asphalt in the presence of a polymerizable monomer. These approaches however, are expensive due to the high cost of the polymer material.
The present invention overcomes the high production expenses of the prior approaches by polymerizing monomers in the presence of or with the asphalt cement directly. The methods of this invention therefore result in modified asphalt compositions which have compositions and structures different from those of the prior art. These inventive modified asphalt compositions exhibit improved physical properties over conventional asphalt cement and at the same time are advantageously produced by an inexpensive production process.